Hydrogen sulfide and/or mercaptans are conventionally removed from hydrogen sulfide and/or mercaptans-containing gases using absorption-desorption processes. The resulting concentrated hydrogen sulfide gaseous stream is then fed into Claus Process to recover elemental sulfur and to recover the fuel value contained in hydrogen sulfide. The tail gas from Claus Process contains trace amount of sulfur compounds which are then removed, for example, using absorption-oxidation processes to ensure the quality of the exhausted gas. The importance of recovering hydrogen and elemental sulfur from hydrogen sulfide has been well recognized in the United States and abroad for some time. U.S. Pat. No. 2,979,384 disclosed a process for hydrogen recovery from hydrogen sulfide using iron, nickel, and/or cobalt sulfides as intermediate chemicals. U.S. Pat. No. 2,984,548 disclosed a process for hydrogen recovery from hydrogen sulfide by passing hydrogen sulfide through a hot tungsten filament.
Reaction of hydrogen sulfide with iodine is a well-known phenomenon. U.S. Pat. Nos. 3,607,004 and 3,716,620 disclosed processes for removing trace amount of hydrogen sulfide and/or mercaptans from gases using iodine in organic solvents. With organic solvents, the advantage of preventing iodine carry-over by the inert gases and the advantage of easy sulfur recovery in crystal form were disclosed in U.S. Pat. No. 3,607,004. As described in details in this invention, I have found that using aqueous systems this invention provides a new and improved process for removing hydrogen sulfide and/or mercaptans from hydrogen sulfide and/or mercaptans-containing gases with proper recovery of elemental sulfur from the resulting aqueous sulfur slurry, and without iodine carry-over by the inert gases. Thermal decomposition of hydrogen iodide is another well-known phenomenon. U.S. Pat. No. 3,365,276 disclosed a process for hydrogen recovery from hydrogen halides where the hydrogen formed by decomposition diffused through a thin silver-palladium alloy tube. British Pat. No. 796,049 disclosed a process for iodine recovery for dehydrogenation of organic materials by passing hydrogen iodide-containing gases through a carbon bed. As described in details in this invention, it provides a new and improved process for hydrogen and elemental sulfur recovery from hydrogen sulfide and/or mercaptans-obtaining gases.